Apparatus for administering anesthetic and nutrient gas under pressure



Se t. 15, 1931. v H. w. c. SCHROEDER 2 APPARATUS FOR ADMINISTERING"ANESTHETIC AND NUTRIENTJGAS UNDER PRESSURE Filed March 22, 1928 PatentedSept. 15, 1931 UNITED STATES PATENT OFFICE HANS WILHELMI CHRIS'I'TANSCHROED'ER, F LUBEGK, GERMANY, ASSIGNOR TO DBAGERWERK, OF LUBECK,GERMANY APPARATUS FOR ADMTNISTERING ANESTHETIO AND NUTRIEN '1 GAS UNDERPRESSURE Application filed March 22, 1928, Serial No.*263,799, and inGermany May 24, 192i.

Operations on the cavity of the chest, as is well known, dare only becarried out, if the lungs from the mouth and the nose are subjected to apressure equal to that exerted by a column of water of 5 to centimetersabove atmospheric pressure, and thus are continuously inflated. It is ofparticular importance that the pressure is not subjected to noxiousfluctuation while '10 the patient is inhaling and exhaling. The

excursions of the lungs if possible should not exceed those caused bythe depth of the breathing. In the devices for ressure inhaling narcosisknown hereto ore, either the fluctuations of pressure are very heavy, sothat the similar heavy movements of the lungs greatly hinder the workingin the field of operation, the thorax being open, or it becomesnecessary to allow large amounts of narcotic gas (50 to 70 liters perminute) to enter and escape, of which that required to fill the lungs issuch a small percentage that it does not materially influence thepressure. Moreover movable compensating vessels loaded with weights orcompressed with gas have been used for receiving and giving out gases,for instance having the shape of bags or bellows. The drawback of suchvessels resides in thisthat they are 39 too idle in commencing tooperate. The bellows material and the load cannot follow quick enough,so that on a frequency of 15 to 20 respirations in the minute considerable fluctuations of pressure say 50% and more occur.

By the apparatus constructed according to the resent invention the saiddrawbacks are re uced to a minimum. This is secured by connecting thebreathing circuit of the 40 device with the inside of a bell adjustablyheld in position within a liquid containing tank. This bell is providedwith a series of gas outlet openings, preferably distributed about thecomplete circumference of thebell at equal depths below the level of theliquid. The bell 'may be adjustable as to height and provided with anykind of device for reading off the difference in level between thesurface inside and that outside the bell. The fluctuations of pressurewith the new apparatus are so slight that they do not trouble theoperator, and the consumption of gas may be reduced almost to thephysiologically necessary amount. The reduction of the gas consumptionhas the double advantage, on the one hand that the costs of theexpensive gaseous anesthetics, for instance azotic protoxide orprotoxide of nitrogen (laughing gas) are cut down to a minimum, and onthe other hand that scarcely any anesthetic vapours are exhaled into theoperating-room. The lading of the air in the operating-room withnarcotic vapours is very injurious to the attendants particularly whenfrequently repeated, an 5 this must be considered a great drawback ofthe pressure, narcosis a paratus requirin a large consum tion 0 gas. 1

t may be remar ed that gasometersf as a reservoir for anesthestics havebeen used heretofore by dentists in their practice.

In the drawing, an apparatus constructed according to this invention isprovided with apressure regulator adapted to be used in connection withanesthesia devices with circulating breathing, though the invention isnot restricted to such devices. The circulatory breathing, that is there-inhaling of the unconsumed gases after exhaling and purifying fromcarbonic acid and water requires as is known a minimum amount of gas,namely scarcely two liters in the minute.

The vessel 1 contains the anesthetic gas and the vessel 2 oxygen. Theflow of both gases is'regulated by the valves 3 and 4 respectively. Thegases flow by, way of the pipes 5, 6 and 7 into the passage 8, and fromthere into the breathing bag 9 or to the mask 11 by way of the pipe orhose 10, respectively. The exhaled gas passes through the flexible pipe12 into the carbonic acid and water absorption cartridge 13 and hencethrough the pipe 14 back into the breathing bag 9. The non-return-valves15 (inhaling valve) and 16 (exhalingvalve) compel the gases to followthe breathing circuit in the manner described. The vent cock 17 servesfor' allowing any surplus of gas to escape from "the circulationoutwardly by degrees or quickly.

The pressure regulating device, by means of which the gas in thecomplete circulating system from the mask to the gas feed pipes 5 and 6is held above atmospheric pressure and by which this pressure can beregulated and held substantially constant, comprises a vessel or tank 18containing water or other liquid and a bell 19 firmly held therein,communicating by a flexible pipe 20 with the passage 8. By. way of thepipe 20 the narcotic gas passes into the bell provided with a pluralityof perforations 21. When there is no possibility of the gasescontinuously paid out by the vessels l and 2 escaping outwardly from theedges of the mask 11 which fits closely and snugly on the face of thepatient, and when the cook 17 is fully or nearly closed, the waterwithin the bell 19 will be displaced until gas freely escapes by way ofthe perforations 21 through the water in the tank 18. The pressure ofthe gas within the bell, which is also the pressure of the gas withinthe breathing circuit, is equal to the depth of immersion of the bellbelow the original level of the liquid in the tank plus the rise of thatlevel due to the expulsion of water from within the bell by the pressureof the entering gas, in centimeters of water. If by way of example thehorizontal cross section of the bell and of the annular space betweenthe bell and the tank 18 are equal, there will be a difference betweenthe inner and outer level of 10 centimeters at a depth of immersion of 5centimeters. The pressure above atmospheric pressure within thebreathing circuit and in the lungs of the patient will then be 10centimeters.

The bell 19 within the tank 18 is adjustable as to height. With thisobject in view the bell has a shaft or rod 23 clamped to a holder orbracket 22 by a set screw 24, which, when loosened, allows of the rodbeing slid up or down to adjust the bell to the desired height,whereupon the screw 24 may be screwed ,up to again firmly hold the bellin adjusted position. Besides means may be provided such as a scale orthe like, which allows of the levels within the tank 18 and within thebell 19 or the difference of the same to be read off. The adjustabilityof the bell together with the means for allowing the levels to be readoff constitute a good and simple pressure adjustin means.

It is of advantage to m e the tank 18 as large as the conditions of theoperating room allow. The cross-section \of the bell 19 must be of theminimum area, such of 1000 square centimeters for example, which hasgiven good results. The amount of air inhaled and exhaled at a medialdepth is about 500 com. and since the breathing bag 9 is generally fullyinflated and only consequently to a certain elasticity is able to giveup and take up a small amount of gas alternatively withdrawn and givenback, the movement of the main amount of gas takes place within thepressure bell 19. Owing to its large area the light liquid water flowsquickly in and out. The level of the water is advantageously subjectedonly to fluctuations of about 0.5 to 1 cm., since the fluctuations ofpressure do not surpass this height. It has been proved that thesefluctuationsof 0.5 to 1 cm. do not disturb the operations in the cavityof the chest nor those on the lungs.

Any amount of gas closed over and above the physiologically necessaramount escapes on every or on every secon or third exhaling by the smallperforations 21 in a number of small bubbles, thus without causingvibratory shocks of pressure. lVhen the patient is inhaling, the waterrising within the bell shuts off the lateral perforations.

The novel pressure regulator if desired may be connected with the pipe14 or with the pipe above the cartridge instead of being connected withthe passage 8 as shown. It may be used in connection with narcosis aparatus for liquid or fluid (vaporous or nebulous) narcotics or withcombined ap aratus for gaseous and liquid narcotics, an also withnarcosis apparatus without circulation.

I claim 1. An apparatus adapted for use in administering anesthetics insubstantially gaseous state under pressure, comprislng a breathingcircuit, a supply of gas under pressure communicating with saidbreathing circuit, a bell of relatively large size connected with thebreathing circuit, a liquid containing receptacle, and means forsupporting saidbell Within the liquid containing receptacle in fixedrelation with respect to said receptacle.

2. An apparatus as set forth in claim 1 in which the bell is providedwith a plurality of perforations spaced equally from the lower edge ofthe bell, said perforations being below the level of the liquid withinthe receptacle.

3. An apparatus as set forth in claim 1 in which the supporting means isadjustable.

4. An apparatus as set forth in claim 1 in which the area of ahorizontal cross section of the bell is substantially equal to that ofthe annular space between the bell and the walls of the liquidcontaining receptacle.

5. An apparatus as set forth in claim 1 I in the breathing circuit.

In testimony whereof I have signed my name to this specification.

HANS WILHELM CHRlSTlA SCHROEDER.

